The Bacillus subtilis menCD promoter is responsive to extracellular pH

Hill, Kevin; Mueller, John P.; Taber, Harry

doi:10.1007/bf00249005

Cited by 16 publications

(12 citation statements)

References 23 publications

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“…Like the sigB operon, menCD is transcribed during stationary phase from a glucoseinducible, A -like promoter (37). One consequence of growth in glucose is the progressive acidification of the medium due to the production of acetate and pyruvate (47), and the menCD promoter has been shown to be responsive to changes in extracellular pH (20). Because B -dependent genes are thought to comprise a general stress regulon (6, 51), the glucose-inducible P A promoter of the sigB operon might also be expected to respond to acid stress.…”

Section: Vol 177 1995mentioning

confidence: 99%

Four additional genes in the sigB operon of Bacillus subtilis that control activity of the general stress factor sigma B in response to environmental signals

1995

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B of the gram-positive bacterium Bacillus subtilis is an alternative transcription factor activated by a variety of environmental stresses, including the stress imposed upon entry into the stationary growth phase. Previous reports have shown that this stationary-phase activation is enhanced when cells are grown in rich medium containing glucose and glutamine. The B structural gene, sigB, lies in an operon with three other genes whose products have been shown to control B activity in response to environmental stress. However, none of these is sufficient to explain the enhanced stationary-phase activation of B in response to glucose. We show here that the four genes previously identified in the sigB operon constitute the downstream half of an eight-gene operon. The complete sigB operon is preceded by a A -like promoter (P A ) and has the order P A -orfR-orfSorfT-orfU-P B -rsbV-rsbW-sigB-rsbX, where rsb stands for regulator of sigma-B and the previously identified B -dependent promoter (P B ) is an internal promoter preceding the downstream four-gene cluster. Although the genes downstream of P B were also transcribed by polymerase activity originating at P A , this transcription into the downstream cluster was not essential for normal induction of a B -dependent ctc-lacZ fusion. However, deletion of all four upstream open reading frames was found to interfere with induction of the ctc-lacZ fusion in response to glucose. Additional deletion analysis and complementation studies showed that orfU was required for full glucose induction of B -dependent genes. orfU encodes a trans-acting, positive factor with significant sequence identity to the RsbX negative regulator of B . On the basis of these results, we rename orfU as rsbU to symbolize the regulatory role of its product.The purpose of many prokaryotic signal transduction pathways is to change the level of transcription of a set of target genes in response to a particular environmental signal. Stress and starvation signals elicit particularly dramatic changes in bacterial gene expression (15,19,21,27,35,46). In a number of cases, these stress and starvation signals have been shown to activate alternative factors that associate with RNA polymerase and reprogram the promoter recognition specificity of the enzyme, thus allowing the expression of new sets of target genes (18,19,32,48). Because factors are such powerful regulators of bacterial gene expression, the signal transduction pathways that control their activation are an area of vigorous investigation.The alternative transcription factor B of Bacillus subtilis is activated upon entry into the stationary growth phase, and this stationary-phase activation is substantially enhanced when cells are grown in a rich medium containing high levels of glucose and glutamine (7,9,25). Significantly, recent work has shown that B is also activated in logarithmically growing cells by a variety of environmental stresses that limit growth, including hyperosmosis, heat, oxidative stress, and ethanol shock (4, 6, 51). These finding...

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Section: Vol 177 1995mentioning

confidence: 99%

Four additional genes in the sigB operon of Bacillus subtilis that control activity of the general stress factor sigma B in response to environmental signals

1995

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“…menF fused to the ninth codon of E. coli lacZ, thereby creating a MenFЈ::LacZ fusion protein (9). To study the expression of menF, strain RB941 was grown in LB medium, LB medium plus 200 M ␣,␣-dipyridyl, and LB medium plus 20 M FeSO 4 .…”

Section: Vol 178 1996 Isochorismate Synthase Genes Of Bacillus Subtmentioning

confidence: 99%

Duplicate isochorismate synthase genes of Bacillus subtilis: regulation and involvement in the biosyntheses of menaquinone and 2,3-dihydroxybenzoate

Rowland

Taber

1996

J Bacteriol

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Bacillus subtilis has duplicate isochorismate synthase genes, menF and dhbC. Isochorismate synthase is involved in the biosynthesis of both the respiratory chain component menaquinone (MK) and the siderophore 2,3-dihydroxybenzoate (DHB). Several menF and dhbC deletion mutants were constructed to identify the contribution made by each gene product to MK and DHB biosynthesis. menF deletion mutants were able to produce wild-type levels of MK and DHB, suggesting that the dhbC gene product is able to compensate for the lack of MenF. However, a dhbC deletion mutant produced wild-type levels of MK but was DHB deficient, indicating that MenF is unable to compensate for the lack of DhbC. A menF dhbC double-deletion mutant was both MK and DHB deficient. Transcription analysis showed that expression of dhbC, but not of menF, is regulated by iron concentration. A dhbA::lacZ fusion strain was constructed to examine the effects of mutations to the iron box sequence within the dhb promoter region. These mutations abolished the iron-regulated transcription of the dhb genes, suggesting that a Fur-like repressor protein exists in B. subtilis.Isochorismate synthase is responsible for converting chorismate to isochorismate and is necessary for the biosynthesis of both the respiratory chain component menaquinone (MK) and the Bacillus subtilis siderophore 2,3-dihydroxybenzoate (DHB) (Fig. 1). Although it is known that the carbon source, growth phase, and oxygen tension have regulatory effects, the actual signals that induce expression of respiratory chain components are unknown (37). However, the production of DHB is known to be regulated by iron concentration (1,25,26). Therefore, isochorismate is required by cells under very different environmental conditions.B. subtilis has two distinct isochorismate synthases encoded by the menF (30) and dhbC (29) genes. MenF and DhbC are 47% identical at the DNA level and have 35% amino acid identity (29). menF is a promoter-proximal gene of the MK biosynthetic gene cluster located at 273Њ on the chromosome (30,38). MK is a lipophilic, nonprotein redox component mediating electron transfer between dehydrogenases and cytochromes (37). dhbC is the second gene of the DHB biosynthetic gene cluster located at 291Њ on the chromosome (29). Under conditions of iron deprivation, B. subtilis synthesizes DHB, a component of the specific transport system for the uptake of extracellular iron (1,25,26). This is not the only instance of gene duplication in B. subtilis. There are two thymidylate synthetases, TSaseA and TSaseB, that are encoded by the unlinked thyA and thyB genes, respectively (22). Both enzymes are functional in bacteria grown at 37ЊC or lower temperatures, but only TSaseA is active at 46ЊC (22). There are two different a-type terminal oxidases in B. subtilis that are encoded by separate loci (32). One of the oxidases is associated with a heme C-containing unit (32). The two membrane alkaline phosphatases of B. subtilis have substantial differences with respect to molecular weight, substrate sp...

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“…In several bacteria, vitamin K 2 (menaquinone) is used during fumarate reduction in anaerobic respiration (11). The genes encoding the enzymes involved in the conversion of chorismate to menaquinone have been cloned in Escherichia coli (12)(13)(14) and Bacillus subtilis (15,16). Although the route of phylloquinone biosynthesis has not been described in cyanobacteria, the pathway is likely to be similar to the pathway of menaquinone biosynthesis in other bacteria.…”

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confidence: 99%

Recruitment of a Foreign Quinone into the A1 Site of Photosystem I

Johnson¹,

Shen²,

Zybailov³

et al. 2000

Journal of Biological Chemistry

132

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Genes encoding enzymes of the biosynthetic pathway leading to phylloquinone, the secondary electron acceptor of photosystem (PS) I, were identified in Synechocystis sp. PCC 6803 by comparison with genes encoding enzymes of the menaquinone biosynthetic pathway in Escherichia coli. Targeted inactivation of the menA and menB genes, which code for phytyl transferase and 1,4-dihydroxy-2-naphthoate synthase, respectively, prevented the synthesis of phylloquinone, thereby confirming the participation of these two gene products in the biosynthetic pathway. The menA and menB mutants grow photoautotrophically under low light conditions (20 E m ؊2 s ؊1 ), with doubling times twice that of the wild type, but they are unable to grow under high light conditions (120 E m ؊2 s ؊1 ). The menA and menB mutants grow photoheterotrophically on media supplemented with glucose under low light conditions, with doubling times similar to that of the wild type, but they are unable to grow under high light conditions unless atrazine is present to inhibit PS II activity. The level of active PS II per cell in the menA and menB mutant strains is identical to that of the wild type, but the level of active PS I is about 50 -60% that of the wild type as assayed by low temperature fluorescence, P700 photoactivity, and electron transfer rates. PS I complexes isolated from the menA and menB mutant strains contain the full complement of polypeptides, show photoreduction of F A and F B at 15 K, and support 82-84% of the wild type rate of electron transfer from cytochrome c 6 to flavodoxin. HPLC analyses show high levels of plastoquinone-9 in PS I complexes from the menA and menB mutants but not from the wild type. We propose that in the absence of phylloquinone, PS I recruits plastoquinone-9 into the A 1 site, where it functions as an efficient cofactor in electron transfer from A 0 to the iron-sulfur clusters.

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The Bacillus subtilis menCD promoter is responsive to extracellular pH

Cited by 16 publications

References 23 publications

Four additional genes in the sigB operon of Bacillus subtilis that control activity of the general stress factor sigma B in response to environmental signals

Four additional genes in the sigB operon of Bacillus subtilis that control activity of the general stress factor sigma B in response to environmental signals

Duplicate isochorismate synthase genes of Bacillus subtilis: regulation and involvement in the biosyntheses of menaquinone and 2,3-dihydroxybenzoate

Recruitment of a Foreign Quinone into the A1 Site of Photosystem I

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